Two axis hand lever

ABSTRACT

A brake or clutch operating device having a hand lever pivotally attached to a mounting bracket secured to a handlebar, the hand lever rotatable about a rotation axis that is offset from the pivot axis, and a transmission mechanism for converting a rotational force applied to the hand lever into a rectilinear force drawing the hand lever toward the handlebar. The transmission mechanism and hand lever configured to force rotation about the rotation axis in response to rotation of the hand lever about the pivot axis, the resulting compound motion of the hand lever following the natural arched motion of the rider&#39;s fingers during lever actuation.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a CIP of Ser. No. 09/123,773, filed Jul. 28, 1998.

TECHNICAL FIELD OF THE INVENTION

This invention relates in general to hand-actuated brake and clutch mechanisms, and more particularly to braking or clutch systems exhibiting an increase in mechanical advantage over the range of motion of a hand lever.

BACKGROUND OF THE INVENTION

Numerous types of bicycle brake mechanisms are known in the art, including drum brakes, cantilever brakes, disk brakes, caliper brakes and linear-pull brakes. One common feature of these brake mechanisms is that the braking force is a function of the force applied to a brake cable extending between the brake mechanism and a hand lever assembly (FIG. 9); a corresponding condition exists for hydraulic brakes. Various mechanisms have been incorporated in braking systems to increase the braking force during lever actuation, providing the rider with increasing braking power or mechanical advantage for slowing the bicycle. The present invention is an improvement to hand-operated braking systems, especially those exhibiting increasing mechanical advantage.

Typically, a hand-operated hand lever assembly consists of a brake handle including a finger grip bar and a cable pulling arm. The hand lever is attached to the bicycle handlebar by a mounting bracket for pivotal movement relative to the mounting bracket about a fixed axis. The brake cable is attached to the cable pulling arm a select distance from the fixed axis. As the finger grip bar is squeezed by a rider of e.g. a two-wheeled vehicle (such as a bicycle or motorcycle), the cable pulling arm pivots, increasing the tension on the brake cable, thereby actuating the brake mechanism. Once the brake mechanism is adjusted, the braking force is a function of how hard the finger grip bar is squeezed. How hard the finger grip must be squeezed and how far it must travel to provide a given braking force is known as the “feel” of the brakes.

Bicyclists, particularly avid bicyclists, each have a preferred feel for their bicycle brakes. Riders tend to anticipate the braking force that will result based upon the feel of their brakes. This feel is particularly important in high performance bicycling, such as off-road mountain biking, where too much braking force under certain conditions can cause the wheels to lock, resulting in a potentially dangerous loss of rider control. Likewise, too little braking force can have disastrous consequences. Thus, not only is a particular brake feel a matter of user preference, in performance situations a consistent feel contributes to rider safety. To complicate matters, as brake pads wear, the feel of the brakes can vary, particularly during off-road biking where dirt and grit increase brake pad wear and where brakes must be used often and aggressively.

With conventional hand lever assemblies, in order for a bicyclist to obtain a desired feel for the brakes, the brake mechanism itself must be adjusted. This is a time consuming and difficult process requiring special tools. Adjustments are particularly difficult under field conditions where a bicyclist either does not have the necessary tools or does not want to take the time to adjust the brake mechanism.

An alternative to adjustment of the brake mechanism to alter the brake feel known in the art, is providing a structure in the hand lever for varying the perpendicular distance between the fixed axis and the brake cable. This distance is known as the pivot arm. Known prior art devices provide a plurality of holes along the length of the hand lever at various distances from the fixed axis. While this structure does provide for coarse adjustment of the brake feel, the adjustment is only between pre-selected distances between the fixed axis and the point of attachment of the brake cable. Thus, only a limited number of pivot arm distances, and therefore brake feels, are available. In addition, while this structure does not require disassembly of the brake mechanism to adjust the brake feel, it does require disassembly of the hand lever assembly to reposition the point of attachment of the brake cable to the hand lever. Thus, adjustment of the brake feel with this structure is time consuming and requires tools which might not be available under field conditions.

Another device employs a slotted hand lever whereby the point of attachment of the brake cable is allowed to transition between varying distances with respect to the fixed axis. Although the noted device provides a varying brake feel and more braking power, one embodiment of the device also suffers from a significant drawback in that there is an abrupt transition of the mechanical advantage and hence, the force applied to the brake cable. The mechanical advantage is inversely proportional to the pivot arm. The smaller the pivot arm, the greater the power or braking force applied to the brake cable. Therefore, it is crucial that the increase in mechanical advantage be smoothly varying and therefore predictable.

Other devices achieve a mechanical advantage increase over the lever rotational range even with fixed cable attachment points, thereby eliminating complex slotted mechanisms while still providing increasing braking power. The brake mechanisms described above, however, all have in common a single axis design feature. The hand lever is pivotally attached to the mounting bracket and as the hand lever is drawn toward the handlebar, the lever sweeps within a single plane of motion. This type of design has several ergonomic drawbacks. In such conventional hand lever designs the rider's hand is forced to slide across the front surface of the finger grip bar and/or the knuckles are pinched upwards as the lever is drawn closer to the handlebar. This configuration not only results in uncomfortable rubbing and chafing of the rider's hand across the finger grip but also weakens the gripping power as the rider's hand is pinched upwards away from the handlebar. Providing a hand lever that simply rotates about a its longitudinal axis alone does not eliminate these drawbacks. Even so configured, the angle that the hand lever forms with respect to the handlebar is typically quite large to provide sufficient lever travel and the rider's hand is positioned further away from the pivot axis to provide the desired braking power. Such a configuration places the lever too far away from the rider's hand, especially for riders with smaller hands, and positions the weaker fingers at the maximum power region on the finger grip away from the pivot axis and the strongest fingers closer in where they are less effective in producing powerful braking.

Thus, it is desirable to provide a hand lever assembly that provides a comfortable hand lever that is easy to reach and that rotates about a second axis to follow the natural arcuate motion of the rider's hand during lever actuation, eliminating friction between the fingers and the finger grip bar while sweeping toward and downward along the handlebar to provide sufficient braking power with desired brake feel. A primary characteristic of the invention is that the arcuate or rotational motion of the provided hand lever is converted into a rectilinear force that boosts the actuating power as the lever is drawn toward the handlebar.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a two-axis hand lever assembly that converts a rotational force, or torque, imparted to the hand lever into a rectilinear force drawing the lever toward the handlebar.

It is a further object of the invention to provide a two-axis hand lever assembly that follows the natural motion of a rider's hand as the rider's fingers sweep toward and below the handlebar, the hand lever rotating to prevent any rubbing between the rider's fingers and the finger grip bar.

It is a further object of the invention to provide a two-axis hand lever assembly including a hand lever that is positioned substantially parallel to the handlebar, providing comfortable lever reach for the rider's hand and maximizing the power imparted by each finger to the finger grip bar, thereby providing “compacted” mechanical advantage benefits over conventional single axis hand levers.

A hand lever actuating system according to one aspect of the invention includes a mounting bracket attachable to a steering handlebar. A hand lever is pivotally attached to the mounting bracket at a pivot axis, the lever also being rotatable about a rotation axis that is offset from the pivot axis. One end of an actuating system cable is attached to the hand lever. A transmission mechanism converts the rotational force, or torque, applied to the hand lever into a rectilinear force, drawing the hand lever toward the handlebar for more powerful actuation of the controlled system. The hand lever assembly has particular application to the actuation of bicycle caliper brakes and motorcycle brakes and clutches. The hand lever assembly may, for example, be used to displace a control cable or to transmit force through a hydraulic line.

Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the invention and their advantages will be discerned with reference to the appended drawings, in which like characters identify like parts and in which:

FIGS. 1a and 1 c are top views of a rack and pinion or geared embodiment of a hand lever assembly according to the invention in which a transmission mechanism of the assembly is disposed on the same side as the finger grip bar of a bicycle with respect to pivot axis A, the hand lever in undeflected and fully deflected positions, respectively;

FIGS. 1b and 1 d are perspective views of FIGS. 1a and 1 c, respectively;

FIGS. 2a-2 c are outboard end views of the geared embodiment of FIGS. 1a-1 d, the hand lever in undeflected, partially deflected, and fully deflected positions, respectively;

FIG. 3a is s top view of a second geared embodiment of the invention in which the transmission mechanism is disposed opposite the finger grip bar with respect to pivot axis A, the hand lever being in an undeflected position;

FIGS. 3b-3 c are end views of the invention of FIG. 3a from opposite ends of the handlebar;

FIGS. 3d-3 f are corresponding views of FIGS. 3a-3 c, respectively, with the hand lever in a fully deflected position;

FIG. 4a is s top view of a third geared embodiment of the invention in which the cable pulling arm is disposed opposite the finger grip bar with respect to pivot axis A, the hand lever in an undeflected position;

FIGS. 4b-4 c are end views of the invention of FIG. 4a from opposite ends of the handlebar;

FIGS. 4d-4 f are views corresponding to FIGS. 4a-4 c, respectively, the hand lever being in a fully deflected position;

FIGS. 5a-5 b are perspective views of an additional embodiment of the invention in which the transmission mechanism comprises a bar linkage, the hand lever being in undeflected and fully deflected positions, respectively;

FIGS. 5c-5 d are side views corresponding to the embodiment of FIGS. 5a-5 b, respectively, with a rider's hand positioned on the hand lever assembly;

FIG. 6 is an exploded view of the components comprising the embodiment of FIGS. 5a-5 d;

FIGS. 7a-7 b are top views of an additional embodiment of the invention in which the transmission mechanism comprises a spooling cable, the hand lever in undeflected and fully deflected positions, respectively;

FIG. 7c is a perspective view of the embodiment of FIGS. 7a-7 b with the hand lever in an undeflected position;

FIG. 7d is an end view of the embodiment of FIGS. 7a-7 c with the hand lever in a fully deflected position;

FIGS. 8a and 8 c are top views of an additional embodiment of the invention in which the transmission mechanism comprises a ball and groove connection, the hand lever in undeflected and fully deflected positions, respectively;

FIGS. 8b and 8 d are side views of the embodiment of FIGS. 8a and 8 c, respectively;

FIG. 9 is a perspective view of a hand lever assembly according to the invention connected by a brake cable to a responding cantilever brake assembly;

FIGS. 10a and 10 b are side views if a hand lever assembly according to a further embodiment of the invention, in rest and fully deflected positions, respectively; and

FIG. 11 is s top view of a geared embodiment of the invention applied to a hydraulic brake system, the hand lever being in a fully deflected position.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENT

Referring to FIGS. 1a-1 d and 2 a-2 c, there is shown one embodiment of the hand lever assembly of the invention. A lever assembly, indicated generally at 10, includes a mounting bracket 20 mounted to a handlebar 22, a hand lever 24 pivotally attached to mounting bracket 20 at a pivot axis A, the hand lever also being rotatable about a rotation axis B, and a transmission mechanism 30. Axis A is, in the illustrated embodiment, orthogonal to and passes above the handlebar axis. Axis B is at a substantial and varying angle to axis A and is roughly coplanar with the handlebar axis, and ends its travel is a disposition roughly parallel to the handlebar axis. A cable 32, such as a brake cable, is routed along a cable guide 34 in turn disposed on mounting bracket 20 and attached to a cable pulling arm 36, the cable pulling arm preferably formed as an extension of hand lever 24. In the embodiment of FIGS. 1a-1 d and 2 a-2 c, the transmission mechanism 30 includes a pinion 40 formed on hand lever 24 in geared engagement with an upstanding rack 42 formed on mounting bracket 20.

In FIGS. 1a-1 b, hand lever 24 is shown in its undeflected or fully retracted position, and is biased to this position by a compression spring (not shown) disposed between lever 24 and mounting bracket 20. During actuation, a rider's thumb hooks around handlebar 22 as an anchor and the rider's fingers grasp a finger grip bar portion 46 of lever 24, causing the hand lever to pivot about axis A and concurrently to rotate about axis B, the rotation about axis B being forced by the transmission mechanism 30. Finger grip bar 46 includes a grasping surface 48 against which the rider's fingers effect an applied force of F₁ (FIG. 2a) during hand lever actuation. At the onset of this pivoting/rotating motion of lever 24, pinion 40 engages rack 42, forcing the lever 24 to be displaced along an arcuate path, both toward the handlebar 22 (shown in phantom) and toward the ground. This arcuate path not only follows the natural motion of the rider's fingers during lever actuation but also converts the rotational force, or torque, applied to finger grip bar 48 into a rectilinear force drawing the finger grip bar toward the handlebar.

The generation of the rectilinear force is best described in FIGS. 2a-2 c. FIGS. 2a-2 b are side views of the hand lever assembly looking inward along axis B in undeflected, partially deflected, and fully deflected lever positions, respectively. Applied forces F1, F2, F3 are shown acting on grasping surface 48 at the center of pressure of the rider's fingers bearing against finger grip bar 46. For purposes of illustration, assume that force applied by the hand is equal throughout lever actuation, F1=F2=F3. Lever 24 is configured to not only pivot about axis A, drawing finger grip bar 46 closer to the handlebar, but also to rotate about axis B, moving the finger grip bar along the front of the handlebar 22 toward the ground. In order to achieve this compound motion, finger grip bar 46 must be configured to cause the load applied by the rider's fingers to shift off-center with respect to rotation axis B during lever actuation, thereby generating the rectilinear force. This rectilinear force is transferred through the cable pulling arm 36 to the brake cable 32. In the undeflected hand lever position of FIG. 2a, applied load F1 acts substantially in-line with axis B, generating an equal and opposite reaction force R1 at a hinge 50 concentric with axis B. Because F1 is not eccentric with respect to R1 (i.e. e1=0), a counterbalancing force is not necessary (i.e. C1=0). In the partially deflected hand lever position of FIG. 2b, however, rotation of finger grip bar 46 has shifted applied load F2 to a new position that is offset from axis B by a distance e2. This load offset causes a rotational imbalance that is counterbalanced by a force C2 acting at a distance e2′ from axis B (i.e. F2e2=C2e2′). The induced counterbalancing or leveraging force C2 in turn drives up the force R2 acting at hinge 50 in order to preserve the load balance (i.e. R2=F2+C2) on the hand lever 24. In other words, by offsetting the same applied force F2=F1 from the rotation axis B, the hinge force R2 is increased by an amount C2, C2 being the rectilinear force generated by the offset rotation moment F2e2. Likewise in FIG. 2c, constant applied load F3=F2=F1 is now further offset by a larger eccentricity e3 with respect to rotation axis B thereby generating an even greater counterbalancing force C3>C2 and inducing a larger hinge force R3. Boosted hinge force R3 provides additional mechanical advantage in comparison with conventional, single axis hand levers, enabling the rider to generate greater actuating power and, as applied to brakes, the desired brake feel. The levers around axes A and B compound to provide a multiple mechanical advantage not possible in a single-axis hand lever.

FIGS. 3a and 3 d are top views of a second geared embodiment of the invention in which the transmission mechanism 30 (in this case, a rack and pinion) is disposed opposite the finger grip bar 46 with respect to pivot axis A, the hand lever 24 in undeflected and fully deflected positions, respectively. FIGS. 3b and 3 c show corresponding side views of the second geared embodiment from opposite ends of the handlebar in an undeflected position, and FIGS. 3e and 3 f show side views respectively corresponding to FIGS. 3b and 3 c, but in a fully deflected position. As in the previous geared embodiment, the hand lever 24 is configured such that applied load F is offset from rotation axis B in a deflected position to achieve the desired increase in mechanical advantage.

FIGS. 4a and 4 d are top views of a third geared embodiment of the invention in which the cable pulling arm 36 is disposed opposite the finger grip bar 46 with respect to pivot axis A, the hand lever 24 in undeflected and fully deflected positions, respectively. FIGS. 4b, 4 c and 4 e, 4 f show corresponding side views of the third geared embodiment from opposite ends of the handlebar. As in the prior geared embodiments, the hand lever 24 is configured such that applied load F is offset from rotation axis B in a deflected position to achieve the desired increase in mechanical advantage.

FIGS. 5a-5 b are perspective views of an additional embodiment of the invention in which the transmission mechanism 30 includes a bar linkage 60, the hand lever 24 in undeflected and fully deflected positions, respectively. As in the previous geared embodiments of the invention, the bar linkage 30 forces rotation of lever 24 about rotation axis B as the lever is pivoted about pivot axis A to convert a rotation force applied to lever 24 into a rectilinear force drawing lever 24 toward the handlebar.

FIG. 6 is an exploded view of the components comprising the embodiment of FIGS. 5a-5 b. Mounting bracket 20 is clamped to handlebar 22 using a screw 21. Hand lever 24 includes finger grip bar 46 hingedly coupled to cable pulling arm 36 at axis B and rotationally fixed to a pivot link 62, cable pulling arm 36 and finger grip bar 46 separated by a bushing 64. Hand lever 24 is pivotally connected to mounting bracket 20 at axis A by a pin. Bar linkage 60 is connected to the hand lever 24 by inserting ball 70 into socket 71 and to the mounting bracket 20 by inserting ball 72 into socket 73, the ball and socket joints being rotatably free.

FIGS. 5c-5 d are side views corresponding to the embodiment of FIGS. 5a-5 b, respectively, showing a rider's hand positioned on the hand lever assembly. As in the previous embodiments, the transmission mechanism 30 and hand lever 24 are configured such that applied loads F1, F2 are offset from rotation axis B at some point during lever actuation. In the hand lever position of FIG. 5c, applied force F1 is already “leveraged” at an eccentricity e1 from axis B thereby inducing a boosting rectilinear force from the onset of lever actuation. As in the geared embodiments, at the onset of lever rotation about axis A, bar linkage 60 (here shown loaded in compression) forces rotation of pivot link 62, and in turn lever 24 about rotation axis B, thereby producing the compound arched motion of the lever toward the handlebar and the ground, while converting rotational moment F1e1, and subsequently larger rotational moment F2e2 (i.e. F1=F2, e2>e1), into rectilinear forces contributing to increased reaction forces R1 and R2, respectively, at axis B.

FIGS. 7a-7 b are top views of an additional embodiment of the invention in which the transmission mechanism 30 comprises an interconnect cable 80 spooling about a groove 82 located on hand lever 24. Interconnect cable 80 is fixedly attached relative to the handlebar 22 at attachment point 84 (or alternatively to mounting bracket 20) draped along groove 82 and attached to the hand lever 24 at attachment point 86. FIGS. 7c and 7 d are perspective and side views, respectively, of the embodiment of FIGS. 7a-7 b, the hand lever in undeflected and fully deflected positions, respectively. Referring to FIG. 7c, lever 24 is configured such that applied load F1 is offset from rotation axis B a distance e1. At the onset of lever actuation, lever 24 pivots about axis A and rotates about axis B with cable 80 being spooled about groove 82 forcing the compound arched motion of the lever 24 toward the handlebar and the ground while converting rotational moment F1e1 into a boosted hinge force R1. In the fully deflected lever position of FIG. 7d, rotational moment F2e2 produces an even greater hinge force R2>R1.

FIGS. 8a, 8 c and 8 b, 8 d are top and side views, respectively, of an additional bar linkage embodiment in which bar linkage 60 is connected to hand lever 24 at attachment point 90 and includes a ball 92 at its other end reciprocally sliding along groove 94 attached to mounting bracket 20. In operation, as lever 24 is pivoted about axis A, the bar linkage 60 rides along groove 94, forcing rotation about rotation axis B. As in previous embodiments, lever 24 is configured such that applied load F2 (fully deflected position) is offset from rotation axis B thereby converting rotational moment F2e2 into a boosted reaction force R2 at axis B.

FIG. 9 is a perspective view of a brake lever assembly according to the invention connected by a brake cable 32 to a responding brake mechanism 100, in which actuation of the lever 24 rotates cantilever arms 110 about pivots 112 thereby causing brake pads 114 to clamp down on a wheel (not shown) located therebetween. While the forms of apparatus herein described constitute preferred embodiments of the invention, it should be understood that the invention is not limited to these forms and that changes may be made therein without departing from the scope of the invention. For example, the hand lever assemblies described herein for use on bicycles, has broad applications to all two-wheeled vehicles using cable actuated braking or control systems.

FIGS. 10a and 10 b show an embodiment in which the lever 24 is rotatable about the pivot axis and also about a rotation axis, as before, showing lever 24 in undeflected and fully deflected positions, respectively. While in this embodiment no transmission mechanism exists to multiply the rider's mechanical advantage, the rotation of surface 46 around two axes permits a more natural, ergonomic fit to the contraction of the rider's fingers. The lever 46 is biased in its undeflected position with respect to axis B by a compression spring (not shown).

FIG. 11 shows an application of the present invention to a hydraulic system in which force is transmitted by fluid pressure. A piston 102 has an end which is operatively connected to hand lever 24. The piston 102 is sealably received within a cylinder 134 that is attached by a pivot or hinge 136 to mounting bracket 20. The cylinder 134 has a port (not shown) which is fluidly connected to the interior of a hydraulic line 132. Leftward (in FIG. 11) displacement of the piston 102 within cylinder 104 places pressure on hydraulic fluid resident therein, in turn creating positive pressure within line 132. This fluid pressure is used to transmit force to a mechanism connected to a far end (not shown) of line 132, such as a brake or clutch mechanism.

A further embodiment of the present invention can also be used to actuate a clutch mechanism for a motorcycle and the like. Drive clutches in motorcycles are typically spring loaded and opened and closed by a hand lever actuating a cable. During periods of frequent shifting, the rider's hand becomes fatigued. The progressive mechanical advantage of the present invention, combined with its two-axis operation, allows the rider to clutch repeatedly with less hand fatigue. While the present invention has been described with respect to brake and clutch applications, it may serve as an actuating mechanism for other mechanically or hydraulically controlled apparatus.

The present invention is not limited by the illustrated embodiments but only by the scope and spirit of the claims which follow. 

We claim:
 1. A operating device, comprising: a nonrotatable bracket for affixation to a handlebar; a hand lever pivotally attached to said mounting bracket about a pivot axis, said hand lever also rotatable, relative to the mounting bracket, about a rotation axis offset from, and not parallel to, the pivot axis; and a transmission mechanism coupled to the hand lever for translating a torque induced about the rotation axis by a first force applied to the hand lever into a second force drawing the hand lever about the pivot axis toward the handlebar.
 2. An operating device according to claim 1, wherein the rotation axis is substantially orthogonal to the pivot axis.
 3. An operating device according to claim 1, wherein said transmission mechanism is provided on said hand lever and said mounting bracket.
 4. An operating device according to claim 1, wherein said operating device includes a cable guide adaptable to receive a cable, the cable being linearly displaced responsive to pivoting and rotation of the hand lever, the hand lever comprising a finger grip bar at a first end of said lever and a cable pulling arm at a second end of said lever for connection to the cable.
 5. An operating device, comprising: a mounting bracket for affixation to a handlebar; a hand lever pivotally attached to said mounting bracket about a pivot axis, said hand lever also rotatable about a rotation axis offset from, and not parallel to the pivot axis; and a transmission mechanism coupled to the hand lever for translating a torque induced about a rotation axis by a first force applied to the hand lever into a second force drawing the hand lever about the pivot axis toward the handlebar, the transmission mechanism including a pinion segment disposed on the hand lever meshing with a rack disposed on the mounting bracket during hand lever actuation.
 6. An operating device, comprising: a mounting bracket for affixation to a handlebar; a hand lever pivotally attached to said mounting bracket about a pivot axis, said hand lever also rotatable about a rotation axis offset from, and not parallel to the pivot axis; and a transmission mechanism coupled to the hand lever for translating a torque induced about a rotation axis by a first force applied to the hand lever into a second force drawing the hand lever about the pivot axis toward the handlebar, the transmission mechanism including a cable interconnect, a first end of said cable interconnect fixed relative to said handlebar, a second end of said cable interconnect operatively connected to said hand lever, a portion of said interconnect being received in a groove formed in said hand lever proximate the second end of said cable interconnect as said hand lever is drawn toward the handlebar.
 7. An operating device according to claim 6, wherein the first end of said cable interconnect is attached to said mounting bracket.
 8. An operating device, comprising: a mounting bracket for affixation to a handlebar; a hand lever pivotally attached to said mounting bracket about a pivot axis, said hand lever also rotatable about a rotation axis offset from, and not parallel to the pivot axis; and a transmission mechanism coupled to the hand lever for translating a torque induced about a rotation axis by a first force applied to the hand lever into a second force drawing the hand lever about the pivot axis toward the handlebar, the transmission mechanism including a bar linkage, a first end of said bar linkage operatively connected said handlebar, a second end of said bar linkage pivotally connected to said hand lever at a location offset from said rotation axis so as to induce rotation of said hand lever about the rotation axis as said hand lever is drawn toward the handlebar.
 9. The operating device of claim 8, wherein the first end of the bar linkage is pivotally connected to the handlebar.
 10. An operating device according to claim 8, wherein the operative connection of the first and second ends of said bar linkage comprises ball and socket connections.
 11. An operating device according to claim 8, wherein the operative connection of a first one of said first and second ends of said bar linkage comprises a ball and groove connection.
 12. An operating device according to claim 11, wherein the first end of said bar linkage comprises a ball and groove connection and the second end of said bar linkage comprises a ball and socket connection.
 13. An operating device according to claim 8, wherein the first end of said bar linkage is operatively connected to said mounting bracket.
 14. An operating device for a cable actuated mechanism comprising: a nonrotatable mounting bracket attached to a handlebar and having a cable guide; a hand lever pivotally attached to said mounting bracket about a pivot axis, the cable guide adapted to receive a cable and the lever adaptable to have an end of the cable attached thereto, said lever rotatable, relative to the mounting bracket, about the pivot axis and also about a rotation axis offset from the pivot axis and having a grasping center point that is offset from the rotation axis, such that a force applied to the lever about the rotation axis at the grasping point of the lever produces a rectilinear force drawing the lever about the pivot axis toward the handlebar and displacing the cable.
 15. An operating device for a handlebar-steered vehicle, comprising: a nonrotatable mounting bracket for affixation to the handlebar; a hand lever graspable by the rider's hand and pivotally mounted to the mounting bracket about a pivot axis, the hand lever further rotatable, relative to the mounting bracket, about a rotation axis offset from the pivot axis; and means coupled to the lever for translating arcuate motion of the lever to actuation force.
 16. A clutch operating device, comprising: a nonrotatable mounting bracket for affixation to a handlebar; a clutch lever pivotally attached to said mounting bracket about a pivot axis, said clutch lever further rotatable, relative to the mounting bracket, about a rotation axis offset from the pivot axis; and a transmission mechanism coupled to the clutch lever for converting a rotational force applied to said clutch lever into a rectilinear force drawing said clutch lever toward the handlebar.
 17. A hydraulic operating device, comprising: a mounting bracket for affixation to a handlebar and having a cylinder for housing fluid; a hand lever pivotally attached to said mounting bracket about a pivot axis, said hand lever rotatable about a rotation axis offset from the pivot axis and having a piston liked thereto which moves within the cylinder to place differential pressure on the fluid; and a transmission mechanism for translating a torque induced about a rotation axis by a first force applied to the hand lever by a first force applied to the hand lever into a second force drawing the hand lever about the pivot axis toward the handlebar, thereby displacing the piston relative to the cylinder.
 18. An operating device for a handlebar-steered vehicle, comprising: a nonrotatable mounting bracket adaptable to be affixed to the handlebar; a hand lever graspable by the rider's hand and pivotally mounted to the mounting bracket about a pivot axis, the hand lever further rotatable, relative to the mounting bracket, about a rotation axis offset from the pivot axis; and a transmission mechanism coupling the hand lever to the mounting bracket to provide a compound leverage of the hand lever about the pivot axis and the rotation axis.
 19. The operating device of claim 18, wherein the operating device includes an elongated flexible control cable, an end of the cable affixed to the hand lever, movement of the lever causing lengthwise displacement of the cable.
 20. The operating device of claim 18, wherein the operating device is selected from the group consisting of braking devices and clutch actuators.
 21. An operating device for transmitting force by displacing a cable along a cable axis, comprising: a mounting bracket for affixation to a handlebar; a hand lever pivotally attached to said mounting bracket about a pivot axis, said hand lever also rotatable about a rotation axis offset from, and not parallel to, the pivot axis, a first end of a linearly displaceable cable attached to the hand lever, the first end displaced from the pivot axis and from the rotation axis; and a transmission mechanism coupling the hand lever to the mounting bracket for translating a torque induced about the rotation axis together with a torque induced about the pivot axis into a force which urges the linear displacement of the cable. 